The performance of woodcutters depends to a great extent, to the condition of their power saws. Therefore, chain saw operators generally sharpen their saw three or four times per day, or more often. Those who are familiar with this art will appreciate that it is at times difficult to sharpen a chain saw while kneeled down to the ground near a chain saw that is loosely laid on an uneven surface. The filing of the chain teeth in these cases is not always effected at the proper angle to give the teeth ideal kerf and pitch. Furthermore, the filling of the chain saw's reservoirs of fuel and chain lubricant when the chain saw is supported loosely, is prone to cause an operator to inadvertently spill gasoline and lubrication oils in the environment. These reasons basically have contributed to the development of a market demand for support devices capable of steadying a chain saw in the forest and allowing an operator to properly file and service the saw.
A number of power saw supporting devices have been developed in the past, and have been used with varying degrees of success. In that respect, a first example of a chain saw vise is illustrated in U.S. Pat. No. 4,109,900 issued on Aug. 29, 1978 to K. E. Vandecoevering. This chain saw vise has a clamp with jaw plates that are operable by wing nuts for attachment to the bar of a chain saw. There is also provided an anvil plate from which a threaded spike extends. In use, the spike is hammered down through the top surface of a stump for retaining the vise to the stump.
Another example of a chain saw vise of the prior art is illustrated in U.S. Pat. No. 4,248,412 issued on Feb. 3, 1981 to L. DeRoy. This invention consists of an L-shaped member equipped with a vise for clamping the bar of a chain saw. A lag screw extend through one arm of the L-shaped member and is adapted to be driven into the top surface of a stump for retaining the device to the stump. The L-shaped member further comprises an adjustable saddle member for supporting the handle bar of a chain saw that is oriented upside down.
Another type of chain saw support device is illustrated in U.S. Pat. No. 4,727,777 issued on Mar. 1, 1988 to J. Obester. In this installation the support device is pivoted on a post which is affixed to the fender of a pickup truck. The support device is conveniently movable from a stowed position along the fender of the pickup truck to an usable position extending away from the pickup truck.
A more recent invention in the field of chain-saw-support devices is described in U.S. Pat. No. 5,816,118 issued on Oct. 6, 1998 to A. Favinger. In this invention, a slotted block and a strap are used for securing a chain saw to a bench. The weight of a person using the bench keeps the bench and the saw from moving during the filing of the saw.
It is believed that aside from retail price and portability, a first requirement by the forestry industry regarding chain saw support devices is that it must contain few moving parts that could become lose and lost. A second preferred requirement by the forestry industry is believed to be that the support device must be capable of supporting a chain saw in such a way that the saw bar may be easily adjusted. Another preferred requirement related to chain saw support devices is that the fuel and chain-oil reservoirs of the saw may be refillable while the saw is still secured to the device following the filing of the chain.
The chain saw support devices of the prior art are believed to be deficient at least one of the above preferred requirements, and it is this reason basically that has contributed to the development of a market demand for a better a chain saw support device capable of satisfying all the preferred requirements of the woodcutting industry.